Draft gear



A g- 1965 D. R. HOLM ETAL DRAFT GEAR 3 Sheets-Sheet 2 Filed July 22, 1963 Wm. wr

INVENTOR. Dona/d fi? /-/a//77 gg/fl/am D. Wallace Wym 1965 D. R. HOLM ETAL 3,202,300

DRAFT GEAR Filed July 22, 1963 5 Sheets-Sheet 3 INVENTOR. Dana/d I? Ho/m United States Patent 3,'22,3ti DRAFT GEAR Donald R. Helm, and William D. Wallace,

Homewood, liIL, assignors to W. H. Miner, Inn, Chicago, Ill, a corporation of Delaware Filed (fully 22, 1963, fier. No. 2%,761 7 Claims. (Ci. 213--22) The present invention relates to a draft gear, and, more particularly, to a friction draft gear which utilizes a stack of pads to resist inward movement of the friction shoes thereof.

The general object of the present invention is to provide a new and improved friction draft gear wherein the resilient pads provide greater shock-absorbing capacity, in the order of approximately 32,006 foot pounds at a reaction level of 500,600 pounds, than comparable A.A.R. standard friction draft gears utilizing coil springs which are rated at an average capacity of approximately 23,000 foot pounds at a reaction level of 350,000 pounds.

Another important object of the present invention is to provide a new and improved friction draft gear of the character described wherein a pair of generally semicylindrical guide or alignment members are disposed about the resilient pads to retain same in columnar stacked relationship.

A further object of the present invention is to provide a new and improved friction draft gear of the character described wherein the guide members are provided on their outer surfaces with projecting bosses and flanges which are engageable with the inner surface of the draft gear casing whereby the guide members and the stack of resilient pads disposed therebetween are retained in properly oriented relationship in the casing.

A still further object of the present invention is to provide a new and improved friction draft gear of the character described wherein a follower is disposed against the outermost resilient pad, which follower is telescopically receivable within the pair of guide members when the draft gear is fully closed and which follower is characterized by a skirt portion within which any resilient pads which are disposed outwardly of the outer ends of the guide members when the draft gear is in its normal condition are confined for stabilization thereof.

Another object of the present invention is to provide an economical easily assembled, and trouble-free friction draft gear with a high maximum capacity for use in railway draft riggings and the like.

Still other and further objects of the present invention will be obvious to a person skilled in the art upon examination of the accompanying drawings and reading of the specification and claims following hereinafter.

in the drawings:

FIGURE 1 is a horizontal central section through a friction draft gear embodying a preferred form of the invention and taken generally on the line 1-1 of FIG- URE 3 with the portion of the view disposed on the near side of the longitudinal center line illustrating the free height positions of the stacks of resilient pads prior to assembly of the friction shoes and wedge member in the draft gear housing and with the portion of the view disposed on the far side of the longitudinal center line illustrating the normal precompression of the stacks of pads after assembly of the friction shoes and wedge member in the draft gear housing;

FIGURE 2 is a vertical section taken generally on the line 2--2 of FIGURE 1 with the draft gear fully closed and with the outer surface of the lower half of the near guide member being shown in side elevation; and

FIGURE 3 is an enlarged scale composite transverse view of the draft gear of FIGURES l and 2 with the portion thereof to the right of the vertical center line being grasses Patented Aug. 24. 1965 and end elevational View and with the upper left and the lower left quadrants of the view being vertical sec tions taken generally on the lines 3aa and S x h-3b, respectively, of FIGURE 1.

As best illustrated in FEGURES l and 2-, the friction draft gear of the invention includes a generally cylindrical casing or housing it) of hexagonal cross section one end of which is closed by an enlarged rectangular end wall or plate 11. The housing MP is provided adjacent its open end with a thick-walled friction shell section 12 of rounded hexagonal cross section, with inner friction surfaces 13 of the friction shell section 12 tapering from its open outer end and converging in a direction toward the closed end of the housing iii. inwardly of the friction shell section 12 and integral therewith is a relatively short transition wall section 14 wherein the inner surface of the housing 10 diverges in a direction toward the closed end of the housing with the housing wall thickness diminishing and tapering into a wall section 15 of uniformly thinner wall thickness. Eight horizontally oriented ribs 17 emerge from the outer surface of the wall section 15 and angle outwardly to suport and reinforce the enlarged rectangular end wall 11 which is thus suitably laterally extended and reinforced so that same is adapted to function as one of the followers of the mechanism for engagement with the usual bufi lugs (not shown) of a conventional draft gear pocket. A pair of diametrically opposite casing holes or recesses 15- are formed in the Wall section 15 of the housing 10 adjacent the end plate 11 and substantially in horizontal alignment with the longitudinal center line of the housing. The open end of the housing it is provided with a series of three circumferentially spaced inwardly turned flange-like lugs 2%) for a purpose to be described.

As is well known in the art, a series of three wing-lil e friction shoes 22 is fitted in the friction shell section 12 in circumferentially spaced relationship. The shoes 22 are characterized by pairs of tapered external friction surfaces 23 which are generally complementary to the friction surfaces 13 of the shell section 12. Inner surfaces 25 of the shoes 22 define an outwardly opening six-sided pocket for receiving the inner end of a wedge 26, which wedge 26 has a flat outer end which is provided with a central recess 27 whereby to define a flat peripheral rim 2% at the outer end of the wedge. The outer end of the wedge 26 is generally circular in cross section with the sides thereof diverging in a direction inwardly of the housing lid in a manner such that a portion of rounded hexagonal cross section is defined midway between its inner and outer ends. The inner end of the wedge 26 is characterized by SiX circumferentiaily arranged friction surfaces 29 which converge sharply in a direction inwardly of the housing it) and are in continuous generally complementary engagement with the inner friction surfaces 25 of the shoes 22. For alignment purposes during assembly, wing portions of two of the friction shoes 22 are provided on their outer surfaces with notches 3i and a pair of indentations or dimples 32 to be radially aligned therewith are provided in the peripheral end 23 of the wedge 26.

In friction draft gears of this general type, resilient means are provided in the housing iii for resisting inward movement of the friction shoes 22 and the wedge 26, with the inner surfaces of the friction shoes 22 being suitably recessed, as at 34-, to provide a seat for such resilient means or any follower device that might be associated therewith.

In operation, as the wedge 26 is moved relatively inwardly of the housing ill) during the application of buff or draft forces to the draft gear, the resilient means resists the simultaneous longitudinal and radial inward movements of the friction shoes 22 whereby to cushion B the buff or draft forces and absorb a substantial amount of same. To retain the wedge 26 and the shoes 22 in the open end of the housing lltl, despite the outward biasing action of the resilient means thereon, the outer periphera1 surface of the wedge 26 toward its inner end is provided with a scries of circumferentially spaced outwardly projecting flange-like lugs 36 which correspond in nun.- ber and spacing to the inwardly projecting lugs 21? at the open end of the housing 19. During assembly of the draft gear, the lugs 36 on the wedge 26 are engaged behind or inwardly of the lugs 24) on the housing 19 whereby the wedge 26 and the shoes 22 are positively retained in the open end of the housing til.

When coil springs are provided for the resilient means in the friction draft gear illustrated and described thus far herein, the draft gear becomes a widely used and commercially successful draft gear which is manufactured and sold by W. H. Miner, inc. and which is known in the trade as the Miner Class A22XL Friction Draft Gear.

This draft gear is rated at a capacity of approximately 23,000 foot pounds at a reaction level of 300,000 pounds. To provide a seat for the inner coil spring of this gear, a protrusion 33, which projects inwardly of the housing from the center of the end wall 11, is provided to receive and position the inner end thereof.

The primary reason behind the development of the present invention was a desire to upgrade or increase the capacity of the Miner A22-XL gear in a simple and economical manner. As illustrated in FEGURES l and 2, the resilient cushioning means of the present invention comprises a first stack of nine compressible rubber or rubber-like elastomeric cushioning pads or units 41 seated against the end plate 11, a first follower 42 disposed against the outermost cushioning unit 41, a second stack of two compressible rubber or rubber-like elastomeric cushioning pads or units 43 seated against the outer face of the follower 42, and a second follower 44- which is disposed between the outermost cushioning unit 43 and the friction shoes 22. Each cushioning unit 41 comprises a disc'shapcd elastomer pad 46 which is interposed between and bonded to a pair of circular metal plates 7 with the diameters thereof being as large as possible While permitting insertion of the units through the open end of the housing 11) past the lugs 24) thereof. The diameter of the cushioning units 41 is therefore considerably less than the inner dimensions of the rounded hexagonal wall section of the housing 1%. The first follower 42 is plate-like in form and has a diameter approximately equal to that of the cushioning units 41. Each cushioning unit 43 comprises a disc-shaped elastomer pad 43 which is interposed between and bonded to a pair of circular metal plates 49 with the diameters thereof being less than that of the cushioning units 41 for a reason that will be evident hereinafter. The second follower 44 is cup-shaped in form and is characterized by a cylindrical base portion 51 of approximately the same diameter as the first follower 2 and by an inwardly directed cylindrical skirt portion 52 which extends partially past the two cushioning units 43 whereby to laterally confine same.

The free height of the stacks of cushioning units 41 and 4-3 after initial assembly of same in the housing 1% is illustrated in the lower portion of FIGURE 1. The normal precompressed height of the same after assembly of the friction shoes 22 and the wedge member 26 in the housing 16) is best illustrated in the upper portion of FIGURE 1. As shown, the inner end of the skirt portion 52 of the second follower 44- is normally spaced a specified distance from the outer face of the first follower 42 whereby to provide for compression of the smaller cushioning units 43 prior to engagement of the first follower 42 by the skirt portion 52 of the second follower 44 during inward movement of the shoes 22 when buff or draft forces are applied to the gear, the cushioning units 41 being compressed upon inward movement of the first follower 42. Full closure of the draft gear is illustrated in FIGURE 2 wherein the cushioning units 41 and 43 are under their maximum compression. As shown, the elastomer pads 46 and 48, in their non-compressed state, have their peripheral edges indented so that when same are compressed at full closure of the draft gear (FIG- URE 2), they do not bulge outwardly beyond theperipheral edges of the metal plates of the cushioning units. The two cushioning units 41 adjacent the end Wall 11 are provided with centered openings 53 so that same may be fitted over the protrusion 38 on the end wall 11.

The shorter stack of cushioning units 43 is retained in centered columnar alignment by the skirt portion 52 of the follower 44 during movement thereof longitudinally of the housing 1b, as during the application and release of buff and draft forces. The wall section 15 of the housing it does not provide suitable guiding action for retaining the cushioning units 11 in stacked relationship during longitudinal movement thereof as the inner dimensions of the rounded hexagonal wall section 15 are considerably greater than the diameter of the units 41. Provision is therefore made for retaining the larger stack of cushioning units 41 in centered stacked columnar alignment in the housing 19 during longitudinal compression of same. As best illustrated in FIGURES 1 and 3, a pair of generally semi-cylindrical sleevclike guide or alignment members 55--55 are longitudinally disposed in the housing 119 in diametrically opposed relationship with the guide members being disposed about the periphery of the stack of cushioning units 41 in a manner such that they retain same in stacked columnar relationship during longitudinal compression thereof. As best illustrated in FIGURE 3, it is noted that the guide members 55-55 are somewhat less than full semi-circles in transverse cross section whereby to facilitate insertion of same,

one by one, into the housing 10 past the lugs 20 at the 7 open end thereof.

To restrict longitudinal and rotational movement of the guide members 5f55 relative to the housing 19, after insertion of the cushioning units 41 therebetween, each guide member 55 is provided at its inner end and approximately midway between its longitudinal edges with an outwardly directed flange-like projection 5'7, which projections extend into the pair of diametrically opposite recesses 19 formed in the wall section 15 of the housing 19 adjacent the end plate 11 whereby to interlock the guide members 55-55 in the housing 1tl. The guide members 5555 are retained in the foregoing interlocked relationship by the cushioning units 41 stacked therebetween. To laterally stabilize the guide members 55-55 and the stack of cushioning units 41 disposed therebetween, two series of circumferentially spaced lbosses 59 are integrally formed on the outer surface of each guide member 55 at opposite ends thereof, which bosses are engageable with the inner surface of the rounded hexagonal wall section 15 of the housing 10, as best illustrated in ElGURE 3, for laterally stabilizing the guide members 555:5 in a manner such that the columnar stack of cushioning units 41 is retained in centered relationship in the housing. As illustrated in FEGURE l, the interlocking projections 57 may be formed integrally on the outer surfaces of a pair of the bosses 59.

As illustrated in the upper portion of FIGURE 1, the longitudinal length of the guide members 55-55 is such that the follower 42 is disposed slightly inwardly of the outer ends thereof when the parts of the fully assembled draft gear are in their normal positions. Thus, when the draft gear is fully assembled, the follower 42 and the stack of cushioning units 41 are at all times retained in their stacked columnar relationship by the guide members 5555. When draft or buff forces are applied to the draft gear, the follower 44, the skirt portion 52 of which serves to retain the cushioning units 43 in properly aligned stacked relationship, is telescopically received within the outer ends of the guide members 5555, as best illustrated in FIGURE 2. To facilitate entry of the skirt portion 52, of the second follower 44 between the guide members 5555, the outer surface of the inner end thereof may be provided with a slight inward taper or bevel as shown.

Since changes can be made in the foregoing structural arrangement and different embodiments of the invention can be made without departing from the spirit and scope thereof, it is intended that all matters shown in the accompanying drawings and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is:

1. In a friction draft gear of the type which is characterized by a generally cylindrical housing having a closed end and an open end which is provided with an internal tapered friction surface, by a series of friction shoes in the open end of said housing and operably associated with said friction surface thereof, and by a wedge member engageable with said shoes and adapted for actuating same upon movement thereof inwardly of said housing, the improvement which comprises, in combination therewith, a longitudinally stacked series of resilient rubberlike pads disposed in centered relationship in said housing inwardly of said friction shoes for resiliently resisting inward movement thereof with the innermost pad being disposed against the closed end of said housing, follower means disposed between the outermost pad and said friction shoes, alignment means disposed in said housing and fitting about certain peripheral portions of said pads for retaining same in said stacked relationship, said alignment means having a non brolten longitudinal dimension which is at least equal to the longitudinal dimension of said stack of pads, and means on said alignment means which cooperate with said housing for preventing longitudinal and rotatable movement of said alignment means relative to said housing and for laterally stabilizing said alignment means in a manner such that said stack of pads is retained in centered relationship in said housing.

2. In a friction draft gear of the type which is characterized by a generally cylindrical housing having a closed end and an open end which is provided with an internal tapered friction surface, by a series of friction shoes in the open end of said housing and operably associated with said friction surface thereof, and by a wedge member engageable with said shoes and adapted for actuating same upon movement thereof inwardly of said housing, the improvement which comprises, in combination therewith, a stacked series of precompressed circular rubber-like pads disposed in said housing inwardly of said friction shoes for resiliently resisting inward movement thereof with the innermost pad being disposed against the closed end of said housing, follower means disposed between the outermost pad and said friction shoes, and a pair of generally semi-cylindrical guide members disposed longitudinally in said housing about said stack of pads for retaining same in columnar stacked relationship during longitudinal compression of same upon inward movement of said wedge and friction shoes.

3. In a friction draft gear of the type which is characterized by a generally cylindrical housing having a closed end and an open end which is provided with an internal tapered friction surface, by a series of friction shoes in the open end of said housing and operably associated with said friction surface thereof, and by a wedge member engageable with said shoes and adapted for actuating same upon movement thereof inwardly of said housing, the improvement which comprises, in combination therewith, a stacked series of precompressed circular rubber-like pads disposed in centered relationship in said housing inwardly of said friction shoes for resiliently resisting inward movement thereof with the innermost pad being disposed against the closed end of said housing, follower means disposed between the outermost pad and said friction shoes, a pair of generally semi-cylindrical guide members disposed longitudinally in said housing about said stack of pads for retaining same in columnar stacked relationship during longitudinal compression of same upon inward movement of said wedge and friction shoes, .an outwardly directed flange-like projection on each of said guide members with said projections being received in recesses formed in the wall of said housing whereby to prevent longitudinal and rotational movement of said guide members relative to said housing, and series of circumferentially spaced bosses formed on the outer surface of each guide member at opposite ends thereof with said bosses being engageable with the inner surface of said housing for laterally stabilizing said guide members in a manner such that said columnar stack of pads is retained in centered relationship in said housing.

4. In a friction draft gear of the type which is characterized by a generally cylindrical housing having a closed end and an open end which is provided with an internal tapered friction surface, by a series of friction shoes in the open end of said housing and operably associated with said friction surface thereof, and by a wedge member engageable with said shoes and adapted for actuating same upon movement thereof inwardly of said housing, the improvement which comprises, in combination therewith, a first longitudinally arranged stack of elastomer pads disposed in said housing inwardly of said friction shoes for resiliently resisting inward movement thereof with the innermost pad being disposed against the closed end of said housing, alignment means disposed in said housing and fitting about certain peripheral portions of said pads for retaining same in stacked relationship, said alignment means having a non-broken longitudinal dimension which is larger than the longitudinal dimension of said first stack of pads, a first follower disposed against the outermost pad and positioned inwardly of the outer end of said alignment means when the draft gear is in its normal condition, a second longitudinally arranged stack of elastomer pads of smaller transverse dimension disposed against the outer face of said first follower, and a second follower disposed between the outer end of said second stack of pads and said friction shoes and being characterized by an inwardly directed skirt portion which is telescopically receivable with in the outer end of said alignment means and within which said second stack of elastomer pads is disposed.

5. In a friction draft gear of the type which is characterized by a generally cylindrical housing having a closed end and an open end which is provided with an internal tapered friction surface, by a series of friction shoes in the open end of said housing and operably associated with said friction surface thereof, and by a wedge member engageable with said shoes and adapted for actuating same upon movement thereof inwardly of said housing, the improvement which comprises, in combination therewith, a stacked series of rubber-like pads disposed in centered relationship in said housing inwardly of said friction shoes for resiliently resisting inward movement thereof with the innermost pad being disposed against the closed end of said housing, alignment means disposed in said housing and fitting about certain peripheral portions of said pads for retaining same in stacked relationship, means on said alignment means which cooperate with said housing for preventing longitudinal and rotatable movement of said alignment means relative to said housing and for laterally stabilizing said alignment means in a manner such that said stack of pads is retained in centered relationship in said housing, a first follower disposed against the outermost pad and positioned inwardly of the outer end of said alignment means when the draft gear is in its normal condition, a shorter stack of rubber-like pads of smaller transverse dimension disposed against the outer face of said first follower, and a second follower disposed between the outer end of said shorter stack and said friction shoes and being characterized by an inwardly directed skirt portion which is telescopically receivable within the outer end of said alignment means and within which said shorter stack of rubber-like pads is disposed.

6. in a friction draft gear of the type which is characterized by a generally cylindrical housing having a closed end and an open end which is provided with an internal tapered friction surface, by a series of friction shoes in the open end of said housing and operably associated with said friction surface thereof, and by a wedge member engageable with said shoes and adapted for actuating same upon movement thereof inwardly of said housing, the improvement which comprises, in combination therewith, a first stack of precompressed circular elastomer pads disposed in said housing inwardly of said friction shoes for resiliently resisting inward movement thereof with the innermost pad being disposed against the closed end of said housing, a pair of generally semi-cylindrical guide members disposed longitudinally in said housing about said stack of pads for retaining same in columnar stacked relationship during longitudinal compression of same upon inward movement of said wedge and friction shoes, a'first follower disposed against the outermost pad and positioned inwardly of the outer ends of said guide members when the draft gear is in its normal condition, a second stack of smaller diameter precompressed elastomer pads disposed against the outer face of said first follower, and a second follower disposed between the outer end of said second stack of pads and said friction shoes and being characterized by an inwardly directed skirt portion which is telescopically receivable within the outer ends of said guide members and within which said second stack of elastorner pads is disposed.

'7. In a frictiondraft gear of the type which is characterized by a generally cylindrical housing having a closed end and an open end which is provided with an internal tapered friction surface, by a series of friction shoes in the open end of said housing and operably associated with said friction surface thereof, and by a wedge member engageable with said shoes and adapted for actuating same upon movement thereof inwardly of said housing, the improvement which comprises, in combination therewith, a stacked series of precompressed circular rubberlike pads disposed in centered relationship in said housing inwardly of said friction shoes for resilientlyresisting inward movement thereof with the innermost pad being disposed against the closed end of said housing, a pair of generaliy semi-cylindrical guide members disposed longitudinally in said housing about said stack of pads for retaining same in columnar stacked relationship during longitudinal compression of same upon inward movement of said wedge and friction shoes, a first follower disposed against the outermost pad and positioned inwardly of the outer ends of said guide members when the draft gear is in its normal condition, an outwardly directed flange-like projection on each of said guide members with said projections being received in recesses formed in the wall of said housing whereby to prevent longitudinal and rotatable movement of said guide members relative to said housing, a series of circumferentially spaced bosses formed on the outer surface of each guide member at opposite ends thereof with said bosses being engageable with the inner surface of said housing for laterally stabilizing said guide members in a manner such that said columnar stack of pads and said first follower are retained in centered relationship in said housing, a shorter stack of smaller diameter precompressed circular rubber-like pads disposed against the outer face of said first follower, and a second follower disposed between the outer end of said shorter stack of pads and said friction shoes and being charac terized by an inwardly directed skirt portion which is telescopically receivable within the outer ends of said guide members and within which said shorter stack of rubber-like pads is disposed.

References Cited by the Examiner UNITED STATES PATENTS 2,808,945 10/57 Danielson 21322 2,855,112 10/58 Withall 213 2,861,696 11/58 Dentler 21345 2,914,196 11/59 Withall 213-45 MILTON BUCHLER, Primary Examiner.

LEO QUACKENBUSH, Examiner. 

1. IN A FRICTION DRAFT GEAR OF THE TYPE WHICH IS CHARACTERIZED BY A GENERALLY CYLINDRICAL HOUSING HAVING A CLOSED END AND AN OPEN END WHICH IS PROVIDED WITH AN INTERNAL TAPERED FRICTION SURFACE, BY A SERIES OF FRICTION SHOES IN THE OPEN END OF SAID HOUSING AND OPERABLY ASSOCIATED WITH SAID FRICTION SURFACE THEREOF, AND BY A WEDGE MEMBER ENGAGEABLE WITH SAID SHOES AND ADAPTED FOR ACTUATING SAME UPON MOVEMENT THEREOF INWARDLY OF SAID HOUSIN THE IMPROVEMENT WHICH COMPRISES, IN COMBINATION THEREWITH, A LONGITUDINALLY STACKED SERIES OF RESILIENT RUBBERLIKE PADS DISPOSED IN CENTERED RELATIONSHIP IN SAID HOUSING INWARDLY OF SAID FRICTION SHOES FOR RESILIENTLY RESISTING INWARD MOVEMENT THEREOF WITH THE INNERMOST PAD BEING DISPOSED AGAINST THE CLOSED END OF SAID HOUSING, FOLLOWER MEAN DISPOSED BETWEEN THE OUTERMOST PAD AND SAID FRICTION SHOES, ALIGNEMENT MEANS DISPOSED IN SAID HOUSING AND FITTING ABOUT CERTAIN PERIPHERAL PORTIONS OF SAID PADS FOR RETAINING SAME IN SAID STACKED RELATIONSHIP, SAID ALIGNMENT MEANS HAVING A NON-BROKEN LONTIDUNAL DIMENSION WHICH IS AT LEAST EQUAL TO THE LONTIDUNAL DIMENSION OF SAID STACIK OF PADS, AND MEANS ON SAID ALIGNMENT MEANS WHICH COOPERATE WITH SAID HOUSING FOR PREVENGING LONGITUDINAL AND ROTATABLE MOVEMENT OF SAID ALIGNMENT MEANS RELATIVE TO SAID HOUSING AND FOR LATERALLY STABILIZING SAID ALIGNMENT MEANS IN A MANNER SUCH THAT SAID STACK OF PADS IS RETAINED IN CENTERED RELATIONSHIP IN SAID HOUSING. 